The present invention relates to a combination type optical disk medium, its reproduction method and an optical disk apparatus.
Following a DVD (Digital Versatile Disk) aiming at conservation of video information, blue-ray (BD) and HDDVD optical disks both aiming at conservation of HDV (High Definition Video) and besides optical disk recording apparatus adaptable to these types of media have been developed. The DVD, BD and HDDVD have different disk formats representative of disk structure and modulation scheme, respectively, and therefore, apparatus dedicated to the individual types of formats and an interchangeable unit compatible with respective formats are needed. On the other hand, the optical disk is a removable medium and is therefore desired to be reproducible with various kinds of apparatus while being as less restricted by disk formats as possible. Under the circumstances, a combination type optical disk has been proposed in which recording layers of a plurality of disk formats are formed in a single disk. For further information of the combination type optical disk medium, JP-A-2006-172574, for example, may be referred to.
Incidentally, a computer, recorder or player unit to be connected to the optical disk apparatus includes a file system as a system for management of data recorded in an optical disk. The file system is a system adapted to identify and manage files and directories contained in an access area, that is, a volume space of the optical disk and as an example, a UDF (Universal Disk Format) adopted in the DVD, BD or HDDVD may be taken up. As for the file system, one may refer to JP-A-2005-174345, for example.